One of the most common sources of knee pain is osteoarthritis, caused by the breakdown of the cartilage that cushions the ends of bones in a joint. In many cases, knee pain caused by arthritis can be alleviated by medications, physical therapy, knee braces, injections of cortisone to reduce inflammation, or injections of hyaluronic acid - a component of the normal lubricating fluid found in the knees - to provide cushioning for the joint.

When there is a severe loss of cartilage due to arthritis, however, the best solution may be knee replacement surgery. In fact, the number of knee replacement surgeries in the U.S. is growing rapidly. The U.S. Centers for Disease Control and Prevention (CDC) estimates that approximately 400,000 Americans had knee replacement surgery in 2007. By 2010, that number had risen to more than 676,000.

For people who would like to learn more about osteoarthritis and the latest advances in knee replacement surgery, Washington Hospital is sponsoring a free seminar on Friday, April 12 from 2 to 4 p.m. in the Conrad E. Anderson, M.D. Auditorium in the Washington West Building, 2500 Mowry Avenue in Fremont. Co-Medical Directors of the Institute for Joint Restoration and Research IJRR) at Washington Hospital, Dr. John Dearborn and Dr. Alexander Sah, will discuss the range of options now available for total and partial knee replacements.

Dr. Dearborn, who performs more than 600 minimally invasive total knee replacement surgeries each year, notes that the choice between total and partial knee replacement depends on the patient's diagnosis.

"Total replacement would be the better option for patients whose cartilage is badly damaged on both sides of the knee and under the kneecap, or for those who have badly damaged cartilage on one side of the knee and under the kneecap," he explains, "Partial replacement would be an option if there is damage on only one part of the knee."

Partial knee replacement offers significant advantages for younger patients whose arthritis has not spread throughout the knee, as well as for older patients with conditions that might limit their recovery from total knee replacement, according to Dr. Sah.

"In a total knee replacement, the ligaments in the center of the knee must be removed," Dr. Sah says. "Partial knee replacement is less invasive, and those ligaments are left intact, so the joint feels more like a 'natural' knee. We also can do surgery just to replace the kneecap. Partial replacements are less costly and patients generally have a faster recovery."

The Case for the "Gender Knee"

Beginning in 2006, Dr. Dearborn began using a new implant, called the Zimmer Gender Knee, which is designed to better fit the anatomy of women, who represent up to 60 percent of all total knee implant patients. Since modern knee implants were introduced in the early 1970s, all designed had been based on average measurements of both men and women, which often resulted in sub-optimal implants for women.

"The end of a woman's femur - the thighbone - generally is shaped differently from a man's, with the side-to-side width narrower than a man's for a given front-to-back dimension," Dr. Dearborn explains. "The standard design for the knee implant that we attach to the end of the femur was adequate for a lot of people, but in many women, if you got the right size implant for the front-to-front width, it was often too wide from side to side."

The Gender Knee also takes into account the fact that a woman's shape generally results in a different angle between the hip and the knee. "Because women's hips usually are wider, the femur comes down at a sharper angle, which affects how the kneecap slides over the femur," Dr. Dearborn says. "The gender-specific knee aligns better to the way the female kneecap tracks."

In some cases, the Gender Knee proved appropriate for certain men, too.

"We assess patients in the operating room to determine which implant will provide the best fit for each patient," says Dr. Dearborn. "It's nice to have an implant with a narrower width for even some men."

Dr. Dearborn and Dr. Sah recently analyzed the database of total knee replacements performed at the Center for Joint Replacement dating back to 2006. Of the 3,897 first-time knee replacements performed, 1,954 - slightly more than half - used the Gender Knee femoral component.

"We performed a total of 2,157 knee replacements in women," Dr. Dearborn notes. "Of those women, 73 percent were considered appropriate for the Gender Knee. We also found the Gender Knee produced a better fit for almost 21 percent of the 1,740 men who received total knee replacements. We're fitting our patients - both women and men - better because of the Gender Knee option."

Dr. Sah recently presented those research findings in Chicago at the national convention of the American Academy of Orthopedic Surgeons.

* Computerized systems that feature a robotic "arm with cutting tools that are guided by plans developed from CT scan data.

"So far, we haven't seen as much improvement in surgical outcomes from these innovations as the manufacturers have claimed," Dr. Sah cautions. "All the marketing promises may not be reality - not yet, at least. The success of total and partial knee replacement surgery still depends greatly on the skill and experience of the surgeons."

Learn More At Upcoming SeminarTo register for this seminar, visit www.whhs.com/event/class-registration.